A lot of neurons have been burned to improve this little part, but the best road derailleurs available are not very different from the SunTour Grand Prix, engineered in 1964 by Nobuo Ozaki. This was the first slant parallelogram derailleur ever. Today many of the little details have been
improved, but the way rear mechanism work is the same.

Luckily for us, those details have made Dura Ace and Record work much better than that old SunTour.

The Dura Ace is a typical Shimano derailleur boosted to the max. Cold
forged aluminum everywhere (A and B knuckles, links, cage plates), a hollow steel attaching bolt that saves some grams, 11 teeth pulleys that turn slower than the conventional ones for a given chain speed, what result in less wear and friction, and also are mounted on sealed bearings, helicoil return spring that insures a constant straight throughout all its stroke, fluorine coated pivots for smooth action.

As in any Shimano rear derailleur the upper pulley allows a little transversal
play. This is very important for a smooth chain transition when using HyperGlide cogs. Do not believe those advertisements that talk about a shifting improvement by mounting a 0 play upper pulley. Shifting will become more noisy and the Rideable Range of Adjustment will become narrower. What is RRA? It is the weapon Shimano has used to conquer the bicycle world. By 1982, and after a bluff with the Positron (1977) and Aero AX (1981) component lines, Shimano tried to find the way to beat SunTour
in the USA.

They started an extensive market research (just as they are doing right now), and they found that the people that was thinking to spend more money in bicycles were yuppies and not hard core bike junkies. Yuppies wanted something looking expensive and techie, but easy to use. The SIS (Shimano Index System ) was the solution. It was introduced in 1985, as a feature
of the Dura Ace EX groupo. Positron was already indexed, but it was a low priced componentry, and low end bicycle builders were not ready in 1977 to control their frame geometry so as to allow a reliable indexed shifting. Shimano learned that such a high precision system needed to be introduced in the high end market.

Shimano based the SIS function reliability on the RRA concept. This meant that the indexed function had to work correctly although the adjustment
was not accurate. Or also: the system has to be rideable even if it is slightly out of tune. To achieve this they found they had to insure a constant gap between the upper pulley and the cogs throughout all the shifting stroke.

So they needed to design their rear derailleur featuring two developments from other companies: The spring loaded main body (The coil that goes around the attaching bolt), introduced by Huret in 1940, and the slant
parallelogram body, patented by SunTour in 1964 as I said above. So Shimano waited for this patent to expire, and this happened 20 years later, in 1984.

The Dura Ace Ex was the first rear mechanism fully computer engineered, and that insured a wide RRA, what meant that users did not needed a mechanic by their side day after day. This meant the beginning of the Shimano Empire, because in the late eighties, a bike without indexed action was almost
impossible to sell, and nobody had the ability to develop such a reliable system, mainly because nobody but Shimano had 200 engineers working in cycle shifters. Later, Shimano developed a bushingless chain that was the first step to the Hyperglide system, and then they introduced the Centeron G (Guide) Pulley. So, NEVER change this pulley for a fixed one, It took a lot of time to develop it.

When Shimano introduced the 9 cog system, the new derailleur (RD 7700)
became compatible with the rest of the Japanese range, while the former Dura Ace (RD 7400) was not because it was still designed under 1985 geometry specifications, that sat a different cable displacement to derailleur displacement ratio. Then Shimano brought also the extension stroke helicoidal spring and the 11 teeth pulleys from the MtB to the road field.

As you can see, this rear mechanism has a lot of history behind it. The result is a very light, silent and reliable action. It feels really accurate.
It also looks great, due to the polished and anodized finishing, much better than the 7400. The spring provides a smooth taste in the larger cogs and a reliable function when downshifting to the smaller one.

The 9 speed system meant a more smooth and silent response for Shimano groupos, and that is evident in Dura Ace.

The Campagnolo Record rear derailleur sets a category by itself. A mechanism that is able to shift between 10 cogs is something only Campy
has, and if you add that carbon link, it is clear there is nothing to compare with it. But that is not all, furthermore that are not the most important features this part has, in my opinion. The carbon link saves some grams , looks great, and sells even better, but Campagnolo did not only took its Record 9s, put narrower pulleys and a fiber link.

They have developed an entirely new geometry that goes a little step further from that ancient SunTour Grand Prix. As I said above, when Shimano
developed the SIS, they found they needed to keep a constant gap between the upper pulley and each cog. So they took the old concept of a spring at the hanger from Huret and they carefully chosen the place where to put the cage pivot. Since then, all derailleurs had a bolt near the hanger to adjust the gap, the way the system could work with different cog sizes.

Until now, because Campagnolo has placed that bolt in the cage pivot. That allows a more accurate regulation, because now the work is done closer to the upper pulley. This also makes the system be more reliable because there are not intermediary parts that can affect this adjustment. With conventional derailleurs, you tune the upper pulley’s gap in the largest cog, and you
have to trust the system to get the right gap in the other cogs. Here, as there is not a single articulation between the place where the adjustment is done and the pulley, there is no possible failure.

Furthermore, Campagnolo has designed a different geometry for this rear mechanism This geometry was needed to reach the accuracy needed by a system
where the cogs are so close as they are here.

While other derailleurs make that pulley describe an arch to pass from the first to the last cog, these new Campy derailleurs move the upper pulley almost in a straight line. All this results in a improved accuracy, because now it is more predictable the path the derailleur will follow each time the cable is pulled. This new geometry is also used now in the 9 speed version of Record. The only difference between the 9 and 10 rear
derailleurs is the thickness of the jockey pulley spacers, and the length of the jockey pulley bolts.

There is also a medium cage version of the 10 speed derailleur with 29 T maximum capacity, so this model must be used if you want to mount the 13-29 T cassette available.

Interestingly, Campagnolo still uses torsion springs for their derailleurs. They argue an extension spring as the ones used for Shimano or SRAM, bring
two problems:

As they cross the rear mechanism main body from the A knuckle’s inner pivot to the B’s outer, you need to design a body that allows such a bulky piece to be there without interfering anything else, and that sometimes means a compromise in derailleur’s performance.

When the mechanism is in the smaller cog position, the spring is almost in its rest position, so its response can be poor.

But, the extension spring concept means a truly advantage because of the linear response it provides through all the stroke. To achieve the same result with a torsion spring, Campagnolo decided in 1996 to develop a conical spring. By two years they announced the spring was made from square section wire, although it really was made of round section one. Finally, the Italians decided to follow with the reliability of round
wire, instead of the strongest response of square wire, due to the risk of strain that this last brings.

Campagnolo’s rear derailleurs springs are quite loaded even in the smaller cog position, so their downshifting response is very reliable.

After all this techno-chat, you will ask: But, does it work? The answer is YES.

This new geometry has really meant an improvement to the already very good performance of former Campagnolo rear derails. The system feels now faster, and, above all, more reliable. No matter if you upshift or downshift 5 cogs in a single push, the chain will not doubt where to go. Together with Ergo levers this derailleur offers the fastest response available.

When pedaling at low cadences, it is the cassette which determines the system’s velocity, because as soon as the chain founds a gate on it, it makes the shift. But, when the cogs turn at a higher speed, it happens that while the derailleur moves from one point to another, one or two gates have passed the upper pulley position, so, in this case, the derailleur’s action plays an important role in how fast the system is.

Here the new Record is a real improvement. It is not the Dura Ace is slow. If you can’t follow your friends (or enemies) in a fast “slide up and down” road, don’t blame Shimano, nobody will believe you. The thing is Record’s response feels as if it read your thoughts: while you push a button, the chain goes from cog to cog, and as the lever is so fast
to pass from a détente point to another, the overall system’s speed is amazing.

I must also say that this is very pleasant for hard-core riders (those with a knife at their teeth), but it could not suit everybody. Maybe the super-plush response of Shimano is better for quiet souled people.

The Record feels (and is) also extremely reliable. No matter how much cogs you up or downshift, no matter if under load, it never doubts. I
can measure the rear derailleur lateral displacement with a tool I made using a 135 mm axle from a Mavic rear hub. I made it gauges with a CNC machine, the way it can measure tenths of a millimeter. It has a piece that slides in the axle and it attaches to the bolt where the upper pulley is mounted at.

This tool gives me the ability to mix shifters and derailleurs of any brand, and then “create” a freewheel or cassette that matches the system.
It also allows to measure out the rear mechanism precision. It happens most systems don’t stop at the same gauge when up-shifting or downshifting. For instance, if you upshift from the smaller to the second cog, the tool reads a distance from the right drop, and if you shift from the third to the second, that distance is one or two tenths more. This increases when doing multiple shifts.

Well, the 10 speed Record is the only rear derailleur I have tested that
ALWAYS gives the same measures on its ten positions. That is why I say it feels and IS reliable.

Front Derailleurs

As the rear derailleurs have to choose between more and more cogs, the front have to have a wider space for the chain to pass and still have
the ability to shift.

The Dura-Ace is part of a indexed system, so it is carefully designed to provide an accurate function.

The most interesting feature of Dura-Ace is its aluminum replaceable cage. It saves some grams the way the overall weight of the derailleur is 79 g.

The distance between pivots is large to improve the system’s rigidity,
and thus, the shifting action. Also, those pivots turn on bushings.

It works very well. The upshift to the larger ring is smooth and the help provided by the Hyperglide design of the sprockets is noticeable. The downshift action is reliable but maybe a little cluncky, not because of the derailleur, but of the shifter, that releases the needed amount of cable very fast. Anyway, nothing important because the chain is engaged on both chainrings during all the action, so you can shift under load.
It is also possible to shift at a while at front and at rear.

The Campagnolo Record looks racing because of the drilled cage. This is another way to save some grams, but not as effective as Shimano’s. Thus the Record tipped our scale at 90 g.

This derailleur works as well with 9 as with 10 speed systems, and features a technopolymer antifriction insert to improve the durability of the C10 chain, and the overall silent action.

And it works really light and accurate. The ExaDrive rings also help, so shifting up and down is really plush. Here, the shifter also helps. When shifting to the smaller ring, the cable is released as you displace the button, so there is not that “hit” from the derailleur cage found on Shimano
systems. This doesn’t mean the campy front system is slow.

If you push quickly, the derail will also move fast, but always with a sweetertaste than the Dura-ace. What takes some time to those who come from Shimano is to learn how much they should displace the button to shift, so it does not need to be trimmed. After a while, you will find yourself doing so without thinking. It is possible too to shift at the same time front and rear without drops or strange sounds.

Cassettes

Much of the work that takes to build a reliable indexed shifting system is applied to this component.Years ago, the cogs from a good freewheel just needed to be hard enough to last a long time, and easy to remove to put a different combination. Nowadays, each tooth is different from the rest in order to reach the best shifting action possible.

I remember the first road 9 speed system I saw was the Dura Ace. Maybe you saw before that “2x9” systems that Ritchey and other smaller manufacturers developed for MtB’s, but it was in February 1996 in Mallorca’s Challenge when I noticed that Rabobank riders were using a Shimano 9 speed prototype.

Now that we all can buy (if we have cash enough) this componentry, we
all can enjoy the smooth response of its Hyperglide cogs.

Depending on the combination chosen, you can found two or three titanium sprockets in it. They are the largest ones, the way the weight saving that this component brings is the highest possible. Also, the four or five largest cogs come riveted to alloy carriers, so as to save a few grams and increase stiffness.

Those combinations that have an 11 teeth cog, have 2 alloy carriers with
2 sprockets in each one, and the largest 2 are made of titanium. The rest have 2 alloy carriers, the first one with 2 sprockets and the largest one with three titanium cogs.

Those cogs that are not made of titanium, are chromoly steel made and heat treated.

Each cog is 1.78 mm thick. Spacers are 2.56 mm wide and made of aluminum.
The distance from the center of one cog to the center of the next cog, measured from the center of one cog to the center of the other one, is 4.34 mm. The inside diameter of each alloy spacer is 33.6 mm.

Although they are called Hyperglide just as 10 years ago, maybe you already know that Shimano’s 9 speed systems have improved noticeably their shifting performance if compared to 8 and 7 speed systems. This is mainly because of the new chains and cassettes, and Dura Ace is not an exception.

Its 9 cog cassette provides very silent transitions of the chain from one sprocket to another, resulting very reliable when shifting under torque. This cassette improves its performance from the 8 cog version of Dura ace when downshifting. It feels almost as smooth as those IG from some MtB 7 cog groupos.

That IG cassettes had special ramps to allow the chain to pass smoothly from a cog to the adjoining, smaller one, that is why they provided a
very plush downshifting action. But, if you look an HG cassette, you will see that, apart from the ramps, all that teeth that are not in a ramp have a special shape that makes impossible for the chain to pass from one cog to another among them. The chain just slips on them, and then, when it reaches a ramp, it jumps to the next cog.

In IG cassettes, sometimes the chain didn’t waited for the downshifting ramps to pass to the next smaller cog, and that resulted in a response
just as with an 7 cog HG cassette. That happened because there was no way to design each teeth the way the chain slid without downshifting.

But with Shimano’s 9 speed cassettes, although the downshifting action is not as smooth as it was with IG when the chain used the ramps, it is always the same, and always better than a 7 or 8 cog HG, so I prefer them.

With its three titanium cogs and the alloy carriers, the 12-23 T combination
we tested weights only 162 g (without lock ring)

We must also say that its durability is way better than a 105 or an Ultegra. In Cantabria, Spain, where is impossible to find a flat ride, it usually lasts around 10.000 km (6000 miles), while these last barely endure 8500 km (5000 miles). In other flatter countries, they last a bit more. Spare cogs are available, so ask at your local shop the price of that ones that start to skip and maybe you can save a few bucks.

The Campagnolo Record cassette’s main characteristic is as simple as to have ten cogs. But, this is something that Daytona and Chorus already offer, so the record goes a step beyond with features enough to be the best of the range of such a prestigious brand as Campagnolo is.

The Italian firm offers two versions for each gear combination: The “budget” one has the four largest cogs made of titanium and the rest of Cr-Va steel
with nickel plated finish. The expensive version is all made of titanium except for the alloy carriers and spacers and the optional steel lock ring. Maybe you are thinking a titanium lockring would be the ice in the cake. Well so they think the guys from Vicenza, and the offer it (only 10 g). If you are going to buy it, be careful and put some anti-seize paste on the thread to avoid galvanic corrosion. Otherwise it will be very difficult to unlock it.

The full titanium 12-23 combo stopped our scale at 137 g without ring, while the “budget” 12-25 set marked 166 g, also without ring. Remember when a 8 speed 12-25 cassette from Dura-Ace, or the steel version of Record weighted 260 g? Maybe we are at the end of the scale race...

The first thing that everybody asks when sees that 1.70 mm thick cogs with a separation from center to center of just 4.12 mm is how much does that last. The answer is quite more than Dura-Ace’s. The Ti/steel version endured 12,000 km (7200 miles). The full Ti version uses to wear a bit faster ( 11,000 km/ 6700 miles). One interesting thing is that all cogs for both versions are available one by one, and their price, although not cheap, is interesting, at least in Europe, so I recommend to purchase
those that start to skip (normally the smaller ones, also the cheaper).

How does it work? It worked good, and now it works much better. Is it like wine, that becomes better with age? No, this is a cassette and not a bottle of Lambrusco (famous wine from the north of Italy), but it happens that the first 10 speed sets available came with Exa-Drive cogs, and although
shifts were accurate, the overall response of the chain going up and down was a little harsh, and it was always possible to hear how it engaged another sprocket.

What happens is that Campagnolo tried years ago to make slight changes in the teeth profile to reach a completely silent response. That started in the cheaper groupo (Avanti) without noticing it not in catalogues nor by press, but it did not liked those hard die Campymaniacs, and they went
back to the original Exa-drive design.

Cassette’s shifting performance was maybe the only criticized thing of ‘2000 Record, so, in February of past year they started again to produce cogs with an improved design (different from the one that was used for a while in the cheaper groupos), again without advice, and by December they made official that improvement calling it UltraDrive.

Wow! And of course it is “Ultra”! It was clear that ExaDrive did not
perfectly fit the C10 chain, and this new design provides a extremely silent and smooth response. I must say that I did not like too much how the former profile worked in the 10 speed groupos, because although it allowed shifting even under high torque, it resulted really noisy sometimes. Now, the UD works as silk, and the slight development difference between cogs and the silent and plush function makes that sometimes you don’t know if there has been a shift or not. I really like how this cassette
performs under the highest torque's. Crisp is the word.

I have already heard some complaints from that rough “Hell Campy Angels”, but my father was one of them, and after a while using the UD, I am sure he would not change it for an ED, although he will never confess so, of course...

And what about the 10 speed matter? It has been the techno chat of the last year in the road field ( and I have even heard discussions between
mountain bikers ). It is clear that if the weakest guy has ten ( or twenty, or three thousands) cogs, he will not win the race. I would also say that the strongest would win even with five cogs if the race is hard enough, but that is not the question.

The thing is, in my opinion,that a tenth cog makes possible to find always the right development. I have found that I use now the big chainring (52 T in my case) in lots of slightly steeped places were I had to shift to
the small ( 39 T ), while downshifting three cogs. That is because now I can reach the 23 cog with the big ring on.

I have also replaced the 39 T ring for a 42T, because now I have that 25 T cog for mountain passes, and this way shifting from a ring to another does not result in such a great change of development, so it is not needed to make multiple cog up or downshifts to compensate that great difference.

This is just an example with my preferences, but there are lots of reasons
that every rider that has tested a 10 speed system finds. Some of them use combos with an 11 T cog, some others the same as me, others come from a triple chainring system and have the 13-29 T version.

This last case is interesting, because the 13-29 T combination, together with a 39 T chainring allows to climb almost every pass with less weight and less mechanical complexity than a triple ring system. You also can use your bike with another cassette in flatter rides, and then it will
be just another two chainring, ten cogs bike with a rear derail that has a slightly longer cage (a special version of the Record rear derailleur is needed to mount this combo), and those days when you need something with shorter gears, you just have to swap the cogs and put the big ones.

This , in joint with the fact that is easier to shift to a larger cog than from a ring to another (you surely will need to downshift two or three cogs to find the right development, and if you are competing with
someone you and your shifters have to be very quick), makes the 10 speed system the faster under those conditions. To be able to enjoy this possibility, I would recommend everyone that is not completely sure of his strength to choose the medium cage version of the rear mechanism, so as not to close the door to the 29 T cog.

In sum, if someone offers you to have a cog more with less overall weight and a better shifting function, would you say no?